﻿<!DOCTYPE html>
<html>
<head>
  <title>Buttons that show on Hover</title>
  <!-- Copyright 1998-2021 by Northwoods Software Corporation. -->
  <meta name="description" content="When the mouse hovers over a node, show a set of Buttons that could perform various actions." />
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <script src="../release/go.js"></script>
  <script src="../assets/js/goSamples.js"></script>  <!-- this is only for the GoJS Samples framework -->
  <script id="code">
    function init() {
      if (window.goSamples) goSamples();  // init for these samples -- you don't need to call this
      var $ = go.GraphObject.make;  // for conciseness in defining templates

      myDiagram = $(go.Diagram, "myDiagramDiv",  // create a Diagram for the DIV HTML element
        {
          hoverDelay: 200,  // controls how long to wait motionless (msec) before showing Adornment
          "undoManager.isEnabled": true  // enable undo & redo
        });

      // this is shown by the mouseHover event handler
      var nodeHoverAdornment =
        $(go.Adornment, "Spot",
          {
            background: "transparent",
            // hide the Adornment when the mouse leaves it
            mouseLeave: function(e, obj) {
              var ad = obj.part;
              ad.adornedPart.removeAdornment("mouseHover");
            }
          },
          $(go.Placeholder,
            {
              background: "transparent",  // to allow this Placeholder to be "seen" by mouse events
              isActionable: true,  // needed because this is in a temporary Layer
              click: function(e, obj) {
                var node = obj.part.adornedPart;
                node.diagram.select(node);
              }
            }),
          $("Button",
            { alignment: go.Spot.Left, alignmentFocus: go.Spot.Right },
            { click: function(e, obj) { alert("Hi!"); } },
            $(go.TextBlock, "Hi!")),
          $("Button",
            { alignment: go.Spot.Right, alignmentFocus: go.Spot.Left },
            { click: function(e, obj) { alert("Bye"); } },
            $(go.TextBlock, "Bye"))
        );

      // define a simple Node template
      myDiagram.nodeTemplate =
        $(go.Node, "Auto",  // the Shape will go around the TextBlock
          $(go.Shape, "RoundedRectangle", { strokeWidth: 0 },
            // Shape.fill is bound to Node.data.color
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 8 },  // some room around the text
            // TextBlock.text is bound to Node.data.key
            new go.Binding("text", "key")),
          { // show the Adornment when a mouseHover event occurs
            mouseHover: function(e, obj) {
              var node = obj.part;
              nodeHoverAdornment.adornedObject = node;
              node.addAdornment("mouseHover", nodeHoverAdornment);
            }
          }
        );

      // but use the default Link template, by not setting Diagram.linkTemplate

      // create the model data that will be represented by Nodes and Links
      myDiagram.model = new go.GraphLinksModel(
        [
          { key: "Alpha", color: "lightblue" },
          { key: "Beta", color: "orange" },
          { key: "Gamma", color: "lightgreen" },
          { key: "Delta", color: "pink" }
        ],
        [
          { from: "Alpha", to: "Beta" },
          { from: "Alpha", to: "Gamma" },
          { from: "Beta", to: "Beta" },
          { from: "Gamma", to: "Delta" },
          { from: "Delta", to: "Alpha" }
        ]);
    }
  </script>
</head>
<body onload="init()">
<div id="sample">
  <div id="myDiagramDiv" style="border: solid 1px black; width:400px; height:400px"></div>
  <p>
    This sample demonstrates buttons that appear when the user hovers over a node with the mouse.
    The advantage of using an <a>Adornment</a> is that it keeps the Node template simpler.
    That means there are less resources used to create nodes -- only that one adornment can be shown.
  </p>
  <p>
    However, using a template as the <a>Part.selectionAdornmentTemplate</a> would allow for more
    than one set of buttons to be shown simultaneously, one set for each selected node.
  </p>
  <p>
    This technique does not work on touch devices.
  </p>
  <p>
    If you want to show such an Adornment on mouseEnter and mouseLeave, rather than on mouseHover,
    the code is given in the documentation for the <a>GraphObject.mouseEnter</a> property.
  </p>
</div>
</body>
</html>